An unresolving painful condition following a trivial peripheral fracture

A 58-yr-old woman presented to our mineral metabolism center, complaining of localized and continuous pain, which worsened with movements, and weakness of the right foot. The patient reported having had a fracture of the fifth metatarsal bone of the right foot about 4 mo ago. She was initially treated with a cast that she did not tolerate and then with an orthopedic brace. After about 1 mo, she noticed swelling of the right foot and started complaining of continuous pain. The physical examination when came to our center seemed partly improved in respect to the initial one referred by the patient even though she still presented with a mild swelling, reddish skin color, and mild sweating on the right foot. Allodynia and hyperalgesia still persisted but at a lower grade. Main biochemical parameters of calcium metabolism were in the normal range. After excluding other clinical conditions, a diagnosis of complex regional pain syndrome type I was made. She was treated with neridronate iv with resolution of symptoms while continuing with physical therapy and pain relievers. Similar milder episodes were reported by the patient in the following months. However, they were immediately resolved by prompt neridronate infusion. No further complaints have been reported during the next 3 yr follow-up.